[s-cars] Spark Plug Torque (was: Oil plug and dynamite)

[Wayne Dohnal]

Since you're a new S-car owner, let me bring something to your attention.
It is vitally important that you check your spark plug torque, preferably
before you drive the car again.  The spark plugs tend to unscrew on their
own, and when they get loose enough, they blow out of the head destroying
the threads in the head, and the coil pack above.  Besides having a disabled
car, you're instantly at least a few hundred dollars poorer.  This has
happened to a number of list members.  The Bentley says the proper torque is
22 ft-lb.  If you're as clueless as I was, the plugs are under the
rectangular cover in the middle of the valve cover.  When you look it won't
be unheard of if one or more of the plug wells is filled with oil.

The plugs ALWAYS work loose after being installed, but they blow out only
occasionally.  After you retorque them 2 or 3 times they seem to stay put.
So if somebody like the dealer puts them in and they aren't checked later,
they will be loose to some degree.  2 of mine were finger-tight when I
checked them.  A number of listers recommend checking them on every oil
change.  Now don't ask me why the oil plug will never come loose because of
dissimilar metals, and the spark plugs will never stay put with the same
dissimilar metals.  Must have something to do with the Audi gods' sense of
humor.  If you replace your plugs, almost all of the listers will tell you
that sticking with the standard F5DPOR is the way to go.  If the timing belt
has 60K miles on it, you should be planning on replacing it.  If the
temperature gauges never come much off of the lower stop, your thermostat is
stuck open, a common failure.

Your valve cover is probably leaking oil in the rear.  When you replace the
gasket it helps to put some RTV gasket maker on the edges of the half-round
plastic plug, which is notorious for leaking.  Another famous quirk is that
if you get wet footwell rugs, it is caused by a blocked drain under the
heater air box (under the hood).  And of course probably half of your little
switch and instrument illumination lights are out, and there's a 50% chance
that one of your front seat heaters doesn't work, and if the gas pedal pad
hasn't fallen off yet, it probably will soon.  These things are all normal,
and you can find help for all of them on the list.

The spark plugs and oil plug are 2 of the worst quirks of the S-car.  But
don't let me discourage you, the positives far outweigh the negatives.
There was an informal poll a while back about how far the engine can go
before needing a rebuild, and the result was that nobody every heard of one
ever getting worn out.

Wayne Dohnal
1994 S4